[#312] wc: Add metrics

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

pkg/local_object_storage/writecache/options.go

@@ -60,6 +60,8 @@ type options struct {
 	reportError func(string, error)
 	// openFile is the function called internally by bbolt to open database files. Useful for hermetic testing.
 	openFile func(string, int, fs.FileMode) (*os.File, error)
+	// metrics is metrics implementation
+	metrics Metrics
 }
 
 // WithLogger sets logger.
@@ -164,3 +166,10 @@ func WithOpenFile(f func(string, int, fs.FileMode) (*os.File, error)) Option {
 		o.openFile = f
 	}
 }
+
+// WithMetrics sets metrics implementation.
+func WithMetrics(metrics Metrics) Option {
+	return func(o *options) {
+		o.metrics = metrics
+	}
+}